Equine veterinary journal. Supplement2000; (29); 81-86; doi: 10.1111/j.2042-3306.1999.tb05176.x

Efficacy of omeprazole paste in the treatment and prevention of gastric ulcers in horses.

Abstract: Equine gastric ulcer syndrome (EGUS) is very common among performance horses, with a reported prevalence of approximately 90% in racehorses, and also > 50% in foals. Omeprazole, an acid pump inhibitor 5 times more potent than ranitidine, has been used with great success to treat EGUS. This multicentre study of Thoroughbred racehorses with endoscopically verified gastric ulcers was designed to demonstrate the efficacy of an equine oral paste formulation of omeprazole in the treatment and prevention of recurrence of EGUS. Of the 100 horses entered into the study, 25 were sham-dosed for the full 58 days of the study. The remaining 75 horses all received omeprazole paste, 4 mg/kg bwt/day once daily for 28 days. At Day 28, 25 of treated horses continued on this dosing regimen while 25 received a half dose (2 mg/kg bwt once daily) and 25 horses were sham-dosed. By Day 28, gastric ulcers were completely healed in 77% of omeprazole-treated horses, while 92% were significantly (P < 0.01) improved. In contrast, 96% of the sham-dosed horses still had gastric ulcers at Day 28. The improvement was maintained in horses that continued on either a full dose or half dose of omeprazole paste until Day 58. However, in those horses that were removed from omeprazole treatment at Day 28, the incidence and severity of the gastric ulcers at the end of the study were similar to those horses that did not receive the omeprazole paste. This study demonstrates that omeprazole paste, 4 mg/kg bwt per os, once daily, is highly effective in healing gastric ulcers in Thoroughbred racehorses and that either a full dose or half dose of omeprazole paste effectively prevents the recurrence of EGUS. The study also indicates that gastric ulcers in untreated horses did not demonstrate a significant rate of spontaneous healing.
Publication Date: 2000-03-04 PubMed ID: 10696301DOI: 10.1111/j.2042-3306.1999.tb05176.xGoogle Scholar: Lookup
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  • Clinical Trial
  • Journal Article
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support
  • Non-U.S. Gov't


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The research study investigated the usage of a paste formulation of Omeprazole, a potent acid pump inhibitor, in treating and preventing the recurrence of Equine Gastric Ulcer Syndrome (EGUS) in Thoroughbred racehorses. The findings indicate that Omeprazole treatment, at either full or half dose, significantly heals gastric ulcers and prevents their recurrence.


  • Equine Gastric Ulcer Syndrome (EGUS) is a pervasive issue in racehorses, with a reported prevalence of approximately 90%.
  • Omeprazole, an acid pump inhibitor five times more potent than ranitidine, has proven effective in EGUS treatment.
  • This study aimed to evaluate the efficacy of an oral paste formulation of omeprazole in treatment and prevention of recurrence of EGUS in Thoroughbred racehorses.


  • The researchers conducted a multicenter study on 100 Thoroughbred racehorses with endoscopically confirmed gastric ulcers.
  • 25 horses served as a control group, receiving a sham dose throughout the 58-day study.
  • The remaining 75 horses received a daily 4 mg/kg body weight dose of omeprazole paste for 28 days.
  • After this initial 28-day phase, the cohort was split into three: a group continuing the full dose, one receiving a half dose, and a group receiving a sham dose.


  • By Day 28, gastric ulcers were completely healed in 77% of omeprazole-treated horses, while 92% showed significant improvement (P<0.01).
  • In contrast, 96% of sham-dosed horses still had gastric ulcers on Day 28.
  • The horses that continued receiving either a full or half dose of omeprazole paste maintained their improvement until Day 58.
  • Horses removed from omeprazole treatment on Day 28 had similar ulcer incidences and severity at study’s end to those never receiving omeprazole.


  • Omeprazole paste effectively treats and prevents the recurrence of EGUS in Thoroughbred racehorses at doses of 4 mg/kg body weight per os, daily.
  • Gastric ulcers in untreated racehorses showed no significant rate of spontaneous healing, indicating the need for a proactive treatment like omeprazole.
  • The study shows the potential promise in using omeprazole paste for other performance horses experiencing EGUS.

Cite This Article

Andrews FM, Sifferman RL, Bernard W, Hughes FE, Holste JE, Daurio CP, Alva R, Cox JL. (2000). Efficacy of omeprazole paste in the treatment and prevention of gastric ulcers in horses. Equine Vet J Suppl(29), 81-86. https://doi.org/10.1111/j.2042-3306.1999.tb05176.x


NlmUniqueID: 9614088
Country: United States
Language: English
Issue: 29
Pages: 81-86

Researcher Affiliations

Andrews, F M
  • College of Veterinary Medicine, University of Tennessee, Knoxville 37901-1071, USA.
Sifferman, R L
    Bernard, W
      Hughes, F E
        Holste, J E
          Daurio, C P
            Alva, R
              Cox, J L

                MeSH Terms

                • Administration, Oral
                • Animals
                • Enzyme Inhibitors / administration & dosage
                • Enzyme Inhibitors / therapeutic use
                • Female
                • Florida
                • Gastroscopy / veterinary
                • Horse Diseases / drug therapy
                • Horse Diseases / prevention & control
                • Horses
                • Kentucky
                • Male
                • Ointments
                • Omeprazole / administration & dosage
                • Omeprazole / therapeutic use
                • Physical Conditioning, Animal
                • Severity of Illness Index
                • Single-Blind Method
                • Stomach Ulcer / drug therapy
                • Stomach Ulcer / prevention & control
                • Stomach Ulcer / veterinary
                • Texas
                • Treatment Outcome


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